function getPro() {
    var FirstDiv = document.querySelectorAll(".product_banxin_topLeft>div");
    var newArr = Array.from(FirstDiv);
    var pro = document.querySelectorAll(".product_banxin_top_right>a")[3];
    var divs = document.querySelectorAll(".product_banxin_bottom");
    var div = Array.from(divs);
    console.log(newArr);//选项
    console.log(pro);//产品
    console.log(div);//介绍
    for (let j = 0; j < newArr.length; j++) {
        newArr[j].onclick = function () {
            for (var i = 0; i < newArr.length; i++) {
                div[i].classList.remove("appear");
            }
            div[j].classList.add("appear");
            pro.innerHTML = this.querySelector("div").innerHTML;
        }
    }
}
getPro();